1. Field of the Invention
The present invention relates to an electron emission elements integrated substrate, more particularly, it relates to an electron emission elements integrated substrate which is effectively applicable to a display device having a flat display surface.
2. Description of the Related Art
A cold cathode type electron emission element has been used as an appropriate element for constituting a display device having a flat display surface which is called flat CRT (Cathode-Ray Tube).
Such an electron emission element is disclosed in, for instance, Japanese Patent Application Laying Open (KOKAI) No. 1-311534. The electron emission element disclosed in the patent document constitutes a surface conductive type electron emission element comprising a pair of electrodes and an electron emission portion of high resistance formed between the electrodes wherein in order to avoid unnecessary spread of electron emission area of the portion, the portion having predetermined minute particles is formed only in a local part between the electrodes.
The flat CRT utilizing the electron emission element mentioned above has not yet widely commercialized. In order to practically commercialize the products of the flat CRT, it is required that the display quality be heightened and that the cost thereof be reduced as well or more than that. For this purpose, it becomes necessary to even the electron emission current of the individual elements included in each pixel by raising the density of the cathodes constituting one pixel of the flat CRT so that an even luminous intensity distribution can be realized over the entire display surface of the CRT. Further, it also becomes necessary to reduce the cost of the electron emission element substrate by raising the through-put of the element production.
However, in accordance with the electron emission element of the related art mentioned above, the electron emission portion is formed by a very complicated process wherein the portion is formed in such a way that first a resist layer is coated on the area other than the electron emission portion so as to form a mask and after that an organic solvent including a palladium compound is coated over an entire surface of the substrate by a spin-coating method and after that the substrate is burned under a predetermined condition to form a discontinuous film having an island structure comprising minute particles of palladium constituting the islands and after that the resist layer is removed. Such a complicated process causes to raise the cost of the element.
Also, at the time of forming the electron emission portion at a local part between the electrodes, the portion is formed two-dimensionally on the surface of the substrate, which limits the high density integration of the electron emission portion which is caused from wiring aspect as well.
Therefore, it was difficult to realize a display device utilizing the electron emission element of high display quality with a low cost.